The Finish Line

The Boston Marathon begins west of the city, in the town of Hopkinton, and because there are 23,336 runners, they are sent off in waves. The wheelchairs go first, followed by the elite women and then the elite men—those who actually have a shot at winning—along with the first great mass of non-elites.

William Evans is in that group. He is 54 years old, and he needs to finish in 3:40 or faster to qualify for next year's marathon. He used to pound out 26.2 miles in well under three hours, but he got older and had his knee scoped and slowed down like most people slow down, only not as much, considering he's still running marathons. He's done forty-four all told, and he's running Boston for the eighteenth time.

Evans knows the course as well as anyone, partly because he's run it so many times but also because he's the Boston cop in charge of security for the miles in Boston proper. Evans is the superintendent of the Bureau of Field Services—the street cops—which means he runs point on logistics for the big events. When the president comes to town or Occupy Boston takes over Dewey Square, his name is on the operational plan. But Evans has this marathon day off.

It's April 15. Five days earlier, a report from the Boston Regional Intelligence Center, which is funded in part by the Department of Homeland Security, warned that the finish line could be bombed. That was the analytical equivalent of telling Evans the sky is blue. Boston police have always known that the middle blocks of Boylston Street could be a target, though it is assumed the most likely moment would be when the elites are loping in. There's always a potential for someone to try to make a name for himself, Evans knows. And if you're gonna disrupt a marathon, you're gonna disrupt the lead runners. So when those lead runners approach, cops on motorcycles and bicycles and foot line Boylston from Massachusetts Avenue all the way to Dartmouth, backs to the course, watching. Make sure we really pay attention to the crowds, the cops are all told.

And the cops always do. The marathon has been run for 116 years without a major security incident, and there's no reason to suggest the 117th will be any different.

10:00: Finish Line

Charles Krupa has photographed the Boston Marathon twenty-four times, every race since 1986 except for the three when the Associated Press posted him to the Philadelphia office. Krupa shoots a lot of things for the AP, but mostly he does sports. Boston's a good town for a sports photographer: He's shot the championships of all four major leagues, been there on the field or the court or the ice, been in the celebrations but not a part of them, the camera lens a small barrier that separates witness from participant.

The marathon coincides with a state holiday, Patriots' Day, the third Monday in April, so traffic is always light on the drive south from New Hampshire, where Krupa lives. He was at the finish line in Copley Square by eight o'clock for his twenty-fifth marathon. It's routine by now. Like riding a bike, he says. He'll shoot from the media bridge spanning Boylston Street a few yards behind the line, like he always does, and his AP partner, Elise Amendola, will shoot from the pavement. He set up a remote camera on a riser to catch the line from the side if the finish is close. He knows exactly what pictures he needs: the wheelchair, men's and women's winners breaking the tape, an emotional reaction shot for each if he can get it, the top American finishers. Then he'll edit those images on his laptop in the media center in the Fairmont Copley Plaza hotel and upload them to the AP's servers. He might shoot a feature later, a runner crawling across the line or something like that guy last year who finished walking on his hands. Or he might call it a day after lunch.

10:15: Finish Line, Main Medical Tent

Earlier, at the eight o'clock meeting for the medical volunteers, one of the supervisors asked how many people were there for the first time.

Michael Powers looked around. He guessed maybe half the volunteers had a hand in the air. Not that it mattered. Rookies aren't the same as novices. On Marathon Monday, the corner of Boylston and Dartmouth streets hosts one of the largest assemblages of medical talent—physicians, nurses, athletic trainers, physical therapists—in the world. The marathon is a prestige event, the most storied road race on earth, and it attracts both the finest runners and the finest professionals to look after them.

Powers is an athletic trainer. He volunteered for his first marathon in 1991. For the past seven years, he's brought students with him from Marist College in Poughkeepsie, New York, where he's the director of the athletic training program. Every time you cover an event, you have a chance to save a life, he tells his classes, and he knows that's true: He once saved a man in cardiac arrest in the stands of a high school basketball game.

Today, though, there mostly will be cramps and blisters and dehydration, possibly some hyperthermia and hypothermia.

There are stations arranged inside the tent to treat the casualties, each with a physician, nurses, an athletic trainer, and a physical therapist. Powers is the captain of the athletic trainers inside the tent, sixteen plus him. Another thirty trainers are outside at the finish line. Last year, when the weather was in the mid-80s, the race was lousy with hyperthermia and dehydration. But this year should be better. The high won't reach fifty under cloudy skies.

10:30: Brighton

Jeff Bauman has never been to the marathon. He's 27 and from Chelmsford, twenty miles northwest of Boston, but he's not a runner and he's never had a runner to wave a sign for.

Erin's a runner, though. He started dating her last June, and now she's his girlfriend and she's in her first marathon, running with Team Stork, raising money for the neonatal and fertility programs at Brigham and Women's Hospital. Of course Jeff is there. He's in Brighton with Erin's roommates, at their apartment. Erin is wearing an RFID chip that is automatically scanned at three checkpoints—ten kilometers, halfway, thirty kilometers—and then again at the finish line, and that data is uploaded to an app so that they can track Erin's progress. When she passes the 10K mark, Erin's averaging 9:22 miles, a four-hour marathon, give or take. They figure they can catch her before the eighteen-mile marker, in Newton, where the course turns sharply right from Washington Street onto Commonwealth Avenue.

11:00: Fairmont Copley Plaza, Elite Athlete Recovery Area

In his day job, Stephen Segatore cares for the gravely ill and the grievously wounded. He's a nurse in the intensive-care unit at Tufts Medical Center, where the doctors and the nurses can perform wondrous medical feats. But they can't save everyone. People die in the ICU. It's part of the job.

He volunteers at the marathon—this is his sixth year, and the first he's been assigned to the elite recovery area—partly as a way to give back to running, which is his sport even though he's not a marathoner. But sports medicine is also an antidote to his job. I like helping healthy, happy people, he says. People don't die at marathons. They just don't.

The elites will barely suffer any wear at all. A few of the wheelchair racers need blisters on the insides of their arms tended, and later one of the elite men will be slightly hypothermic. But by midafternoon, the Fairmont Copley Plaza ballroom will be quiet, and Segatore will wander to the main medical tent, in case they need an extra nurse there.

12:50: Newton

Jeff Bauman and his girlfriend's roommates are in Newton, at the corner near the firehouse, when Erin is just beyond the halfway point. The crowd is dense, the sidewalks crammed with spectators, and the course is thick with runners. He's afraid he'll miss Erin in the river of faces. They have a sign, though: RUN, ERIN, RUN! Hopefully she'll see the sign.

Ten minutes and hundreds of runners pass. Twenty minutes, thirty. And then she's there in her dark blue tank top with the Team Stork logo, baby blue, in the center. Her stride is steady, and she's clocking 9:13 miles. Jeff calls to her, and she detours to the side, wraps Jeff and her roommates in a quick hug, gives Jeff a kiss. Then she turns back into the stream, and Jeff watches as she jogs east on Commonwealth until she disappears into the throng.

1:40: Finish Line

Superintendent William Evans crosses the finish line three hours and thirty-four minutes after he started, a comfortable six minutes under his qualifying time. To his right, near the bleachers, he sees a black Lab, one of eleven bomb-sniffing dogs working the street and the subway station. The elites have long since finished, but there are still thousands of runners on the course, and the first big wave is just starting to roll down Boylston. The police aren't relaxing.

Evans heads to the recovery area. He gets some water and wants a massage, but the tables are all full, the wait too long. He meets his wife and youngest son at a hotel around the corner and drives them home to South Boston. Then he heads to the Boston Athletic Club, also in Southie. It's where the local cops host their brethren from out of town who come to run the marathon. Also, there's a hot tub. Evans slips into it and starts to soak away the miles.

Superintendent of Field Services. In charge of the operational plan for the race._

2:30: Finish Line

At about two o'clock, Jeff Bauman and Erin's roommates hailed a cab to Back Bay, then walked the last few blocks to the finish line. Bauman thinks Erin could have finished strong, come in under four hours, so he wants to see if she's in the recovery area. They look for ten minutes. They don't see her. They move west on Boylston, walk to the other side of the finish line.

Temporary metal fencing, waist-high, lines the sidewalk, and one of the roommates, Michele, is right against it with her camera. The other, Remy, is tiny, only about five feet two. She can't get a clear view for pictures. Bauman is tall and lean, and Remy asks if she can get on his shoulders.

He laughs, tells her no. Remy shrugs, then slips away, back toward the buildings and a little ways down the sidewalk, to find something to stand on.

2:40: Fairmont Copley Plaza, Media Center

Every year after the marathon, Charles Krupa and Elise Amendola make a pilgrimage to a bar, always a different one, where they raise a toast to their old boss at the AP. By two forty, Krupa's ready to go. He'd shot each of the winners by a quarter past noon, and it took him a couple of hours to edit and file his pictures from his laptop in the Oval Room of the Fairmont Copley Plaza. The Oval Room is elegant and mannered, except on marathon day, when tally boards cover the paintings and rows of long, narrow tables are squeezed in for the global media.

Krupa's gear is packed. He's waiting for Amendola, ready to leave as soon as his partner shows up.

2:48: Finish Line

Bauman is peering down Boylston, his head turned to the right, watching for Erin. There is a man standing next to him, close off his elbow. The man is wearing dark glasses and a dark baseball cap and a dark jacket that seems to Bauman to be some kind of leathery hoodie thing. He has a backpack slung over one shoulder. The man in the glasses looks at Bauman, holds the gaze until Bauman looks away. But the man doesn't look toward the runners. He's not watching the marathon, and he's not smiling, and he's not with any friends. He doesn't look like he's having any fun, Bauman thinks. I've got a bad feeling about this guy.

The marathon clock, counting from the last start time, reads 4:08. Bauman wonders if he missed Erin behind the finish line. He wants to go look again. He doesn't know she cramped up after the 30K checkpoint, slowed her pace. He takes a few steps back from the fence. The man in the glasses is gone. Bauman sees a black backpack on the sidewalk. It occurs to him that at the airport a disembodied voice is forever telling people to be aware of unattended packages. He thinks he should tell a cop about this particular unattended package. The marathon clock clicks to 4:09.

Inside the Fairmont Copley Plaza, Charles Krupa hears a tremendous metallic bang that reverberates and echoes. It sounds like a Dumpster dropped by a garbage truck in an alley before dawn. His gut tells him he's just heard a bomb, but his head just as quickly tells him that can't be true. He wonders if a forklift breaking down the staging might have dropped a scaffold.

Stephen Segatore hears a sound like a steel plate dropped onto cement from twenty feet. Then he feels the puff of a pressure wave that flutters the soft sides of the tent.

Michael Powers is talking to one of the physicians and another athletic trainer in the medical tent, remarking how good the weather's been for the runners. He hears a bang, like a big firecracker, only an order of magnitude louder. He tells them, "That wasn't thunder."

2:49: Finish Line

Jeff Bauman hears only a pop. Or it could've been pop pop pop. He won't remember exactly.

Then he's on the ground, a haze of smoke above him. He hears screaming, dull through his blown-out ears. He can see Michele in front of him. She's down, too, near the fence. Her leg is bleeding, and he can see the white of a bone in her lower leg where the flesh has been torn away. Oooo, Bauman thinks. That's not good.

Nothing hurts. He tries to prop himself up, but he can't. Then he sees his own legs. His feet aren't there. His ankles, parts of his shins, gone. His legs end short in shreds of flesh and jagged bones.

He's hemorrhaging, and his clothes are smoldering, burning into his back, his sides, his right arm. He reaches for his cell phone, thinks he should call someone, but he can't find it.

He believes he is going to die.

2:49: Finish Line, Main Medical Tent

Michael Powers hears a second bang. He opens a seam in the sidewall of the tent and slips out onto Dartmouth Street. People are running toward him, away from Boylston, tumbling past in a frantic jumble. The gray facade of the library blocks his view around the corner, but he starts moving against the stream on instinct and adrenaline.

He sees the smoke as he comes around the corner. He sprints to the barriers on the north side of Boylston. On the sidewalk, beyond the fencing, he sees bodies, maybe ten of them, in a tangled heap. Shattered glass glints on the sidewalk. And there is blood, so much blood, bright red and everywhere.

Michael Powers (center, in white) in the immediate aftermath of the first blast.

2:50: Fairmont Copley Plaza, Media Center

A security guard is hollering in the Oval Room. "We're all in lockdown now," he says. "There's been an explosion. The hotel is in lockdown."

Krupa realizes the AP doesn't have a photographer outside. He scans the Oval Room. Already guards are posted by the two marked exits. But he's been in this room so many times, he knows there's a third way out, a door adjacent to the podium where race officials give updates to the press. That door is unmarked and, at the moment, unguarded.

He grabs his gear, hustles out that third door and into a small corridor near one of the hotel's secondary exits to the street. Three guards are fiddling with it, working a key into the lock. They have their backs to him. Krupa doesn't break stride, squeezes between them, pushes through the door and out onto Saint James Avenue.

"Hey," one of the guards yells. "The hotel's locked down." "I gotta go," Krupa says, not looking back, starting to trot across the plaza. He checks his equipment, clicks two quick frames with his wide-angle, makes sure everything is properly set. Then he runs toward the finish line.

2:50: Finish Line

A man in a cowboy hat is leaning over Bauman. "Don't move," the man tells him. "Just don't move."

The man in the hat uses his hands to smother Bauman's burning shirt. A woman's sweater, white and lost in the panic, is on the sidewalk. The man grabs it, tears off the sleeves. Someone else is with him now. The man wraps one sleeve around each of Bauman's thighs, tightens them into tourniquets.

A woman appears with a wheelchair. "He's gotta go," the man in the hat tells the woman. He turns to Bauman. "I'm going to pick you up now."

Bauman manages to get his arms around the man's shoulders while the man reaches under his back and what's left of his legs. The man lifts as gently as he can, sets Bauman in the chair. "We need to move quick," he tells the woman. "We need to move now."

How a Victim Became a Hero

Even a bomb blast couldn't knock the image of Tamerlan Tsarnaev from Jeff Bauman's memory. Recovering from a double amputation, Bauman gave investigators the clues they needed to crack the case. —John B. Thompson

Tuesday, April 16

In the intensive-care unit of the Boston Medical Center, Jeff Bauman wakes up from heavy anesthesia and asks his half brother Chris for a pen and paper. He writes, "Bag. Saw the guy. Looked right at me." Using Bauman's description—baseball cap, sunglasses, stubble— an FBI sketch artist renders a portrait that looks almost like Tamerlan Tsarnaev.

Wednesday, April 17

In part thanks to Bauman's description, the FBI is able to isolate a potential suspect in security-camera footage taken along Boylston Street. Further investigation prompts the bureau to suspect an accomplice, a young man in a white hat.

Thursday, April 18

Unable to identify the suspects, the FBI releases images to the public. Record traffic overwhelms the FBI website, and calls flood the FBI tip line. Boston police commissioner Edward Davis calls this night "a turning point of the investigation." The suspects are identified as Tamerlan and Dzhokhar Tsarnaev.

The chair is off the sidewalk, into the street, the woman pushing from behind, the man in the hat on the right side, pulling by the arm. The wheelchair stutters, skids. The sleeve wrapped around Bauman's right thigh has come loose, dangled over the side, gotten tangled in the wheel. The man in the hat pulls it clear and the wheelchair is moving again, and he keeps pace, holding the loose end of the tourniquet and trying to pull it tight.

···

Finish Line

Krupa charges toward the finish line, still not sure exactly what's happening. He sees smoke, a skittering swarm in the street. In the near distance, moving fast toward him, he sees a man in a cowboy hat running next to a wheelchair, a woman pushing. A step closer, he sees the man in the chair, ash gray and still. Krupa runs toward them, gets near, then starts stepping backward to keep pace and stay out of the way. Through his lens, he sees what remains of Jeff Bauman's wrecked legs.

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Finish Line, Main Medical Tent

Stephen Segatore gets to the front of the tent, out on the street, starts toward the finish line. A wheelchair is coming fast. The man in it is gray, not moving, and his lower legs have been torn away.

Segatore says to himself: Holy shit.

He's seen such injuries before, but only on stable patients in the ICU. People in car crashes, mostly, or construction workers who get tripped up on the job. Those are violent wounds, trauma by force.

The volunteers and the runners in the tent part automatically, clear a path from the front to the back. A handful of ambulances have been staged there all day, and more already are screaming in. The tent has converted instantly into a front-line mass-trauma triage facility.

The wheelchair doesn't slow down until it's out the back of the tent, where Bauman is loaded into an ambulance.

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Finish Line

Michael Powers pulls open a gap in the fence, moves toward the bodies. He sees a woman on the sidewalk, her pants smoldering, and he can see both of the broken bones in one lower leg poking through the skin. He swats at her pants, slaps out the embers. He has no supplies, no gauze or bandages, so he grabs a T-shirt off the ground and presses it against her mangled leg.

There is a small boy by the woman's head, her son. Powers is on one knee, and he reaches for the boy, pulls him onto his thigh. The boy tells Powers his name is Noah and he is 5 years old. Also, his leg hurts. Powers sees an abrasion, as if the boy had scraped it on the sidewalk or been grazed by shrapnel. "It's okay," he says. "You're going to be all right."

"No," Noah says. "It's my other leg." Powers turns his head to get a look at Noah's other leg. There's a void where a piece of his calf should be. Powers clamps a hand over the wound in Noah's leg, keeps the pressure on his mother's leg. He squats like that, holding two legs, for what seems like a very long time.

···

South Boston

Superintendent Evans is still soaking out the miles. Cecil Jones, the president of the Boston Police Runner's Club, rushes toward him, brisk and purposeful. "Super," he says when he gets to the edge of the tub, "two bombs just went off at the grandstand." Evans is out of the tub immediately, showers quick. His uniform is at home, so he stops there, double-parks, and runs inside. The marathon took the spring out of his legs, but he's moving fast. He gets back in his car, guns it, runs the blue lights and siren all the way into Back Bay.

···

Finish Line, Main Medical Tent

More wounded are coming through the front of the tent. A voice on the loudspeaker, smooth and baritone, is telling the volunteers, "Do what you know how to do. Help where you can."

Segatore sees a man on a cot, a burn on the side of his face. Segatore helps cut his clothes off to see if there are other visible injuries. There aren't, so he moves on to the next patient, another man. A piece of his calf has been blown away, and the man is screaming that he can't leave, won't leave, until he finds his daughter. Segatore stabilizes the wound, but he can't help search for the little girl.

More wheelchairs, more stretchers. Segatore sees a third-year resident running beside a gurney, doing chest compressions on a body. An EMT is holding a ventilator bag over the patient's face.

Segatore takes over for the EMT on the ventilator. The patient is a woman, young. She's unconscious and alabaster pale. The left side of her body, from the pelvis down, is pulp. Segatore tells her he's a nurse, that she's in the medical tent. He tells her, "We're going to help you."

AP photographer. Positioned at the finish, his twenty-fifth year shooting Boston._

Back Bay

Jeff Bauman is in an ambulance. An EMT talks to him, keeps him awake, sort of alert.

Bauman is pretty sure he's going to live.

Boston Medical Center is a mile and a half from the marathon tent. Before the ambulance pulls in front, Bauman tells the EMT, "I know who did it." And when he's out of the ambulance, rolling fast toward the operating room, there's a cop trotting next to the gurney. Bauman tells him the same thing. I know who did it.

The OR is prepped and ready. Bauman is inside and anesthetized minutes later, and surgeons begin cutting off the ruined ends of his legs.

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Finish Line

Police officers pull away the sheathing on the bleachers, and other cops sweep the sidewalk, peeking in and around and behind any crevice or object that could be concealing another bomb.

Powers watches them from the sidewalk, where he's still kneeling and pressing on two wounded legs. A year earlier, Powers took a training course in mass-casualty disasters. The instructors set up a mock school shooting, a school-bus crash, a bus bombing. The bombing was pretty realistic: smoke heavy in the air, casualties on the ground. He'd run to them, pretend-treating pretend wounds. Then an instructor blew a whistle, told everyone to stop. "You're all dead," he'd said. "There was a secondary device." The instructor pointed at a briefcase lying next to a mailbox. "It just went off, and you're all dead."

It has not occurred to Powers to be frightened, running toward the blasts instead of away. But those cops still make him feel better.

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Finish Line, Main Medical Tent

The pale woman has a pulse, but only because Segatore is pumping her heart. An EMT brings a monitor, connects it. The line on the screen jumps, but it's an illusion: PEA, pulseless electrical activity, which means the body's electrical signals are firing but the heart isn't contracting.

Segatore has his hand on her arm when a doctor tells him to stop trying to save her.

Do what you know how to do, the voice on the loudspeaker says again. Help where you can.

Other nurses need the stretcher. Segatore helps move the woman to a cot, covers her with a blanket, arranges other cots around her like ramparts. Then he looks at the young volunteer who fetched the blanket to cover the body. "Fuck," he blurts at him. Fuck. People don't die at marathons.

But right now there's another woman on another stretcher, blood spurting from an arterial wound in her ankle and a bulge in her other leg, her tibia fractured and pressing against the skin. Segatore puts a fast, crude dressing on the ankle, and a physician manipulates the broken bone into place.

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Finish Line

One of Powers's students appears with bandages. They wrap Noah's leg, mom's leg, help get them into wheelchairs. Powers means to tell the EMTs to keep Noah and his mom together, but everything is happening so fast, and the boy is gone before he can get the words out.

He turns back to the pile of bodies. The smell of burnt flesh hangs near the ground, a stink he knows from sawing cadavers. He sees a couple, late twenties, both in bad shape. The man's lower leg has been nearly blown away—I don't know where his fibula is—hanging on by only a few thin strands of soft tissue. Powers swaddles the wound as best he can, not expecting to save the leg but maybe to keep it from falling off when the man gets moved.

There's another body on a backboard. Powers helps carry the board and the patient into the tent. He doesn't know how bad the injuries are or even if the person on the backboard is a man or a woman, because he never bothers to look. Along with everyone else, he's just trying to get the wounded into ambulances as quickly as possible.

And when the victims are all gone, there still will be runners in the tent, just as dehydrated and cramped as they were at 2:49, only traumatized now, too. Powers will stay until six o'clock, tending to them like he volunteered to do in the morning.

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Finish Line

Superintendent Evans is blocked by barricades even his car can't get past. He catches a lift to the edge of Copley Square and covers the last block on foot, adrenaline making up for what the marathon wore out.

It's taken him almost thirty minutes to get from Southie to the finish line. He is awed by what he sees.

Later, investigators will learn each of the two bombs was a pressure cooker packed with shrapnel—ball bearings, nails, BBs—and powder from dismantled fireworks. Later still, they will learn that the bombs were allegedly placed on the sidewalk by two brothers of Chechen descent living in Cambridge. Evans will see video from surveillance cameras of the moments after the explosions, and he will be proud just as surely as he is sickened. He'll see Officer Christine Carr stripping off her gun belt and then her trouser belt, wrapping the latter around a man's hemorrhaging leg, tightening it. He'll see Officer Thomas Barrett on his hands and knees, slapping at a man on fire, then rolling him over and patting down his back.

But Boylston Street is strangely quiet now. The wounded have all been removed. All that's left is the wreckage: metal fencing toppled into the street, the glint of shattered glass, bright red smears on the sidewalk. Evans has seen training films of bombings in Israel. The aftermath looks the same in Boston as it does in Tel Aviv.

Nurse. Assigned to the Elite Athlete Recovery area in the Fairmont Copley Plaza hotel. _

There are still officers on the street, state cops and Boston cops and federal agents, securing the scene, already gathering evidence. A block and a half down Boylston, where the second bomb detonated in front of a restaurant called Forum, there are also two bodies: Lu Lingzi, a 23-year-old student from China, and Martin Richard, an 8-year-old from Dorchester. A third body, that of the pale woman Segatore and the others tried to save, is still in the medical tent. Her name was Krystle Campbell, and she was 29. Evans hates that the bodies are still out there, hates that they can't be gently moved away. But the dead are evidence now. There may be clues in where and how they fell, and there may be evidence, traces of the bombs, on their bodies. They need to be examined and processed, and so they will lie where they died until long after dark.

···

Lockdown

The center of the city is locked down, Boylston cordoned off from Hereford Street to Berkeley, twelve square blocks in all. It is the largest crime scene in Boston history, and it is painstakingly examined by technicians in white hazmat suits.

Officially, the bombings are a federal investigation, overseen by the FBI. But Boston cops and federal agents get along better than ever these days. State police and transit police and National Guardsmen and ATF agents are in the streets, too. Boston is an occupied city, a heavily armed camp in and around Copley Square, the police presence thinning farther from the epicenter.

On Tuesday, investigators find parts of the bombs—a circuit board, batteries, wires, fragments of the pressure cookers—on the sidewalks and in the street and even on rooftops. By Wednesday, they know almost exactly how they were assembled and detonated. Other agents are looking at tens of thousands of images, stills and movies from spectators and video from surveillance cameras, and by Thursday afternoon they have clear pictures of two suspects.

A few hours later, likely spooked by their faces on television, Dzhokhar and Tamerlan Tsarnaev, 19 and 26 respectively, allegedly shoot an MIT police officer named Sean Collier in the head, apparently in a failed attempt to steal his gun. Then they carjack a Mercedes SUV (again, allegedly) and wander around Brighton and Cambridge before driving into neighboring Watertown.

Superintendent Evans, like a legion of other officers, has worked more than seventy-two straight hours by then, catching naps when he can. He races out to Watertown that night, after the Tsarnaevs start a gunfight in the street that Tamerlan loses. And he's in Watertown the next night, when Dzhokhar is found hiding beneath the tarp of a wintered-over boat. That was Evans's voice on the radio, screaming Hold your fire! Hold your fire! after one officer fired a round at the boat—why is unclear—which got a bunch of other officers shooting, too. And Evans was there when Dzhokhar was on the ground, wounded but alive. There's no way he would have missed that, no way any of the cops would have.

"They messed with us," Evans said later. "And we took it personally."

···

By that Friday night, the media narrative shifts from the dead and the wounded to the bad guys. Krystle Campbell and Martin Richard and Lu Lingzi become "three killed," and all the others are abbreviated to "more than 260 wounded."

Those are grotesque numbers, even without faces and names attached to them. If there is any comfort in them, it is only that the first one—three dead—could have been so much higher. That so many medical personnel were assembled on-site was fortuitous, as is the fact that Boston has five level-one trauma centers within a five-mile radius of the finish line. But that so many people ran toward the smoke and the blood, that so many strangers tied tourniquets and pushed wheelchairs and dressed wounds, is astounding. Stephen Segatore eventually learned that ninety-seven of the most seriously wounded were triaged and evacuated in twenty-five minutes. Later, a doctor in one of the ERs marveled to him about seeing "all these horrifying wounds on remarkably stable patients."

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FBI agents were waiting for Jeff Bauman when he woke up on Tuesday. They had a sketch artist with them who listened as Bauman described the man he knew dropped the backpack that blew off his legs: dark glasses, dark cap, dark jacket, dark hair. It wasn't a perfect description, but it made it easier to pick faces out of the crowd on the surveillance tapes.

By the morning after the bombing, Charles Krupa's picture of Bauman and the man in the cowboy hat had been published all over the world, though often cropped so the most horrific damage wasn't visible. Bauman had become, literally overnight, the face of the Boston Marathon bombing. And when word got out that he'd been able to give investigators a description, he became one of the heroes, too.

So did the man in the hat. His name is Carlos Arredondo, and he is from Costa Rica. Krupa didn't recognize him in the moment, but he realized later that he'd photographed Arredondo twice before, first protesting the Iraq war and again in 2006 when Arredondo became a U.S. citizen. The reason he was considered newsworthy enough for the AP to twice photograph is that he was mildly and heartbreakingly famous: In August 2004, when three Marines came to tell him his son Alexander had been killed in Iraq, Arredondo in his grief and rage splashed gasoline on his body and lit himself with a propane torch.

He'd been passing out small American flags all morning on Marathon Monday so people on the sidewalks and in the bleachers could wave them at twenty National Guardsmen who were marching the route with rucksacks to raise money for Military Friends Foundation. One was marching in memory of Alexander.

Arredondo passed out 200 flags and then went back and got 200 more to give away in the bleachers. He had one left when the first bomb went off. He saw a ball of fire roll up from the ground and a man tumble over the metal fencing, and then everything—the people, the sidewalk, the buildings—disappeared in a shroud of gray-white smoke. He was halfway across the street when the second bomb blew up, and he crossed himself and begged God protect me, but he kept running. And then he found Jeff Bauman, ripped the sleeves off a sweater for tourniquets, and heaved him into a wheelchair.

He does not know why he did that, why he ran toward the bedlam. He says only that he knew people would be hurt, but that's an observation, not an explanation.

About the same time Krupa realized he'd photographed Arredondo twice before, he remembered that a few weeks earlier he'd also shot the Costco in Nashua, New Hampshire, where Jeff Bauman works the service deli. It occurs to him that Boston, in many ways, is a very small town.

Krupa muses about this a couple of weeks after it all happened, when he's had time to digest everything he saw through his lens, when he's had time to consider the odd connections. He doesn't know why Arredondo ran to help instead of running away, either.

"But I would hope," he says, "that if I ever needed it, people would do for me what I saw people doing for everyone else that day." His eyes are wet, and he swallows hard. "I hope I would do it, too."

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